No, what html format do you have in mind for bookmarks? xml? At the moment there is no way to make folders or subfolders

It Is in this site https://nostrools.netlify.app/bookmarks.html you can download as html and import on your bookmark web.

You would have to parse all the html to convert it to the proper format. It could be an interesting option, although at the moment I do not have in mind to develop it

thanks all the same, I'll just use the links then